Reading environment variables with Javascript

Question

I need to read the system time from the environment variables on the client's OS. I searched on Stackoverflow and found that this isn't possible. However, those answers were from 2010 and I want to ask if anything has changed since.

Is it possible with some kind of framework? or Javascript is still sandboxed and cut off from OS?

Answer 1

szpic, if Javascript were not sandboxed from the OS, any half-witted criminal could get onto your computer and take control. Allowing environmental variables is way too low level to ever be allowed.

Take a look at all of your environmental variables and ask yourself if everyone on the planet should have access to all that data about your computer.

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If you want to do this with Javascript, you'll have to use a special web browser, such as node-webkit. It isn't going to run on any normal web browser, though, so don't expect more than 0.0001% of the population to expect to run your page.

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I don't know your intended use, but one trick, to throw in an environmental variable, is to make a shortcut to your web application, and include it in there as a URL parameter (at least on Winblows).

http://myapp.com?computername=%COMPUTERNAME%

Answer 2

the javascript Date() Object provides the clients system time.

Answer 3

FWIW.... Just playing around with an .HTA file (yes that uses the MSIE 'engine' so you can probably forget about other browsers) and the following JavaScript reads the %TEMP% path variable to set a filepath+name for safely writing a temporary file. This works OK for me :

var oTest = new ActiveXObject("wscript.shell");
pathTest = oTest.ExpandEnvironmentStrings("%TEMP%") + "\\test_it.txt";
oTest = null;
alert(pathTest);  // proves we can read %TEMP%

// and create the file, to complete the example
var oFSO = new ActiveXObject("Scripting.FileSystemObject");
var fil = oFSO.CreateTextFile(pathTest, true);
fil.WriteLine("Hello wonderful world!");
fil.Close();